Peristaltic micropump and related systems and methods

ABSTRACT

A peristaltic micropump includes one or more flexible channels configured to transfer one or more pumped fluids, and an actuator configured to engage the one or more flexible channels and rotate about a central axis. The actuator includes a plurality of rolling elements and a driving element configured such that the driving element operably rotates about the central axis and each rolling element operably rolls about a respective axis that is not parallel to the central axis. The plurality of rolling elements is disposed between the one or more flexible channels and the driving element. The driving element includes a cage configured to capture the plurality of rolling elements such that the plurality of rolling elements is located at different radii from a center of the cage.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional patent application of U.S. patentapplication Ser. No. 15/820,506, filed Nov. 22, 2017, now allowed, whichitself is a divisional patent application of U.S. patent applicationSer. No. 13/877,925, filed Jul. 16, 2013, now abandoned, which is a U.S.national phase application under 35 U.S.C. § 371 of International PatentApplication No. PCT/US2011/055432, filed Oct. 7, 2011, and claimspriority to U.S. Provisional Patent Application Ser. No. 61/390,982,filed Oct. 7, 2010, the entire contents of which are incorporated hereinby reference.

FIELD OF THE INVENTION

The present disclosure relates generally to peristaltic micropumps andvalves and related systems and methods, including microformulators,mixers, and other valved systems incorporating peristaltic micropumps.

BACKGROUND INFORMATION

Fluid flow in microfluidic devices can be driven and controlled by avariety of mechanisms, including differences in external hydrostaticpressure between inputs and outputs of a device, the use of electricforces with either dielectrophoresis or electroosmosis, actuation bypistons and/or valves, or by peristaltic action induced by a movingcompressional wave induced in an elastic fluidic conduit.

Microfluidic devices for chemical or biological research offer thepromise of automated complex analysis with fast reaction times and smallsample consumption. For example, optimization of chemical synthesispathways or formulation of chemical solutions on a chip is potentiallyvery fast since many alternatives can be explored in a short timeperiod, and only very small quantities of expensive or rare drugs orreagents are required. In addition, drug discovery experiments in whichmany chemical compounds and/or combinations thereof are screened by thestrength of a cellular response may be conducted with greater speed andreliability. There is virtually an infinite number of potentialapplications of microfluidic devices since in theory any biologicalassay may be reduced in scale, even very complex functions that wouldnormally be studied in vivo. For example, Harvard researchers haverecently published extensive work on a lung on a chip that breathes, hasits own blood circulation, and mounts its own immune response tobacterial invasion (see “Reconstituting Organ-Level Lung Functions on aChip” Dongeun Huh, Benjamin D. Matthews, Akiko Mammoto, MartinMontoya-Zavala, Hong Yuan Hsin and Donald E. Ingber, Science, 328,1662-1668, 2010).

However, for this type of technology (commonly referred to as “Lab on aChip”) to be integral components of real, marketable devices, it isimportant to be able to control and move many discrete small volumes offluid on the chip with little dead space and without long time delays.It has been demonstrated that the exemplary embodiments of rotary planarperistaltic micropumps (RPPM) are capable of pumping a wide range offlows that are appropriate for microfluidic experiments. An RPPM canalso be readily incorporated directly into a microfluidic chip, and itsfunctionality when integrated with microfluidic networks will beenhanced by a proximal and reliable means of switching fluidic inputsupstream or fluidic outputs downstream from the pump body. An on-chippump with switchable inputs and outputs lends flexibility tomicrofluidic design and allows the construction of more complex devicescapable of more sophisticated sample-processing tasks.

There are many examples of microvalves in the scientific literature (seeOh et al., A Review of Microvalves, J. Micromech. Microeng., 16,R13-R39, 2006, incorporated by reference herein) that utilize a widevariety of materials and actuators. Embodiments of a rotary planar valve(RPV) described herein are a unique extension of RPPM technology. Incertain embodiments, the actuator comprises a caged thrust bearing withrolling elements turned by a motor, crank or other rotational device.While similarities exist between the technologies, one differencebetween RPPM and RPV embodiments includes the geometry of themicrofluidic channels that are compressed by the rolling elements.Unlike prior art devices, certain exemplary embodiments of the presentinvention utilize the concept of a rolling element being rolled in acircle over one or more channels in an elastomeric material by arotating flange that has a matched, elastomeric driving surface.

Exemplary embodiments of the RPV described herein are small and can belocated near an on-chip pump such as the RPPM. This enables the designof low volume fluidic circuits with rapid transit times, low deadvolumes, and the possibility of recirculation and feedback. Althoughpopular existing technology using pressurized, pneumatic controlchannels is also small-volume (see Unger, et al., MonolithicMicrofabricated Valves and Pumps by Multilayer Soft Lithography,Science, 288, 113-116, 2000; and Melin, et al., Microfluidic Large-ScaleIntegration: The Evolution of Design Rules for Biological Automation,Annu. Rev. Biophys. Biomol. Struct., 36, 213-231, 2007, eachincorporated by reference herein) exemplary embodiments of RPPM/RPVtechnology have an advantage of being driven by electric motors—a small,inexpensive, relatively simple, robust and mature technology, incontrast to the solenoid bank and source of pressurized gas for thepneumatic valve controller. While the pneumatic valves can be configuredso that in the absence of gas pressure the valve can either be normallyopen or normally closed, the design determines the resting and activatedconductances—these pneumatic valves cannot be toggled to remain ineither state arbitrarily without the continual application ofpressurized gas to maintain one of the two states.

In contrast, embodiments of a motor-driven RPPM can function as a valvewhen the motor is stopped. In certain embodiments, the RPV is anextension of this concept in which multiple (e.g., up to sixteen ormore) separate fluidic channels or conduits are routed through thecompression zone of the thrust bearing of an RPPM. In any givenrotational position, the rolling element at rest compresses and occludesa predetermined number of channels, and rotation of the bearing into aset of rotational positions actuates the valve. Importantly, the fluidicchannels can be oriented and sized so as to eliminate or minimize fluiddisplacement during actuation of the RPV. Complete elimination ofdisplacement removes the possibility of errors in downstream chemicalcomposition that may arise from residual volumes of displaced fluid.

One type of valve that can be created from this mechanism is an N-to-1valve in which N input channels may be switched to connect to one outputchannel. Reversed, the same device connects one input to one of Noutputs. This is similar in concept to a mux, demux or mux/demuxcombination switch in electronics (an abbreviation of multiplexers anddemultiplexers). In the standard pneumatically actuated microfluidicvalve, multiple solenoids are required to control multiple inputs. Inthis RPV embodiment, a single motor can control sixteen or more inputs.Other more specialized valve constructions that perform the microfluidicequivalent of a large number of combinations of multi-pole, multi-throwelectronic switches can be built from the basic RPV platform.

In certain embodiments, RPVs can be configured wherein precise angularcontrol of the caged bearing is provided by, for example, a steppermotor or a DC gear-head motor with an angular encoder, so that the ballsor other rolling elements can be positioned exactly over a particularchannel at a particular time. In some implementations, the balls wouldbe rotated intermittently in a single direction, whereas in others, themotion would be alternately over a small angle to move a ball back andforth against a particular channel. In that latter case, a means ofdetermining the exact position of the balls may improve the performanceof the device.

In other implementations, the continuous rotation of the ball cageprovides intermittent connection to multiple channels, so that the exactangle is not as important as the angular velocity. In these cases, asimple DC motor or a DC motor with gear head but no encoder would besufficient.

One feature of exemplary embodiments of the RPPM and the RPV is that nopneumatic connection is required to control the microfluidic device.Hence this approach is particularly suited for applications wherein adisposable microfluidic cassette is inserted into, for example, apoint-of-care reader, and a lever or other mechanical actuation means isprovided to move the rolling elements into contact with the PDMS orother elastomeric device such that the underlying channels arecompressed to allow pumping and valving operations.

This disclosure includes a variety of designs that can be implemented byvarious combinations of RPPMs and RPVs, or RPPMs with pneumatic valves.Several of these implementations demonstrate that the RPV and/or RPPMcan be used to provide a concentration of a chemical that varies in timeeither in a sinusoidal manner or with some other chosen waveform, forexample, to allow large-amplitude, different-frequency modulation ofvarious chemical concentrations in a chemical reaction network toidentify reactions whose rates are determined by the product of two ormore concentrations. This would be difficult to achieve withconventional peristaltic pumps and on-chip microvalves.

Exemplary embodiments of the present invention include devices andmethods of peristaltic pumping. In the classical, macroscopicperistaltic pump (FIG. 1), a pump body (101) constrains a deformableplastic tube (102) that is compressed by three or more rollers (103).The rollers are caused to rotate by coupling to a central rotor (104),which is caused to rotate about an axis (105). As a result, fluid isdrawn into one end of the tubing (106) and expelled from the other(107). Many different techniques have been developed to simplify andstreamline this method of fluidic pumping. In microfabricated devices,however, there have been only a limited number of implementations ofperistaltic pumps.

In Darby et al. (2010), this system is implemented in a microfluidicdevice using either a rotating cam with the “tubing” wrapped around thecam, or a linear screw drive pressed against a series of microfluidicchannels (FIGS. 2A and 2B). In the rotating cam version, encapsulatedchannels (201) are created by bonding together two thin layers (202) and(203) of a deformable polydimethylsiloxane (PDMS) polymer (one flatlayer and one layer with channels). These encapsulated channels areanalogous to the classic peristaltic pump's tubing, and are wrappedaround a thin cylindrical mandrel and then cast in a thick PDMS layer(204) that provides mechanical support and serves as the pump body (101)in FIG. 1. After curing, a cam with an oval-shaped cross section (205),with a transverse diameter greater than that of the diameter of theoriginal cylindrical cam, is fitted into the cylindrical hole left bythe original mandrel, producing two points of compression (206 and 207).As this cam is turned (208), the two points of compression drive fluidalong the channels, achieving peristaltic flow from 209 to 210. With thelinear screw model, the difficult process of wrapping the channels iseliminated. The basic pumping concept is similar to the rotating camversion. A screw (211) is placed such that its major axis is parallel tothe fluid channels (212), and fluid flow is then achieved by rotatingthe screw (213). The screw is held in place over the channels by a castlayer of PDMS (214), which also provides the requisite compression (215and 216). As the screw rotates, the threads move along the channels,producing flow from 217 to 218.

Two other early implementations of peristaltic pumps in microfluidicdevices use either an array of solenoid-actuated pins that sequentiallycompress zones along a microfluidic channel cast in PDMS (Gu et al.,2004, and Takayama et al., 2010) (FIG. 3), or three or morepneumatically actuated membranes that also provide sequentialcompression of a channel (Chou et al., 2001) (FIG. 4). In the former, aPDMS microfluidic device mounted on a rigid substrate (301) has one ormore channels (302) that are compressed by pins (303-305) that aredriven by solenoids, often using an apparatus found in a tactileBraille-reader head. The sequential compression of the pins draws fluidinto the channels (306) and drives fluid out of the other side (307). Asfor the latter, the pins' functions are replaced by pneumaticallyactuated channels (401-403) contained in a second PDMS membrane (404)bonded to the membrane (405) containing the channels (406) to becompressed. Pressure applied to channels in the second membrane causesthe channel to expand (401) and depress the membrane that forms thebottom of the upper channel, and therefore induce compression (407)along the lower channel within a microfluidic device backed by a rigidsubstrate (408). When adjacent channels in the upper membrane aresequentially actuated, a compression wave moves along the channels inthe lower membrane and fluid is drawn from 409 to 410. In the event thatpumping is not desired, both approaches require the dissipation of powerto keep at least one channel closed to prevent passive flow or backflowthrough the pump.

Another method of inducing peristaltic compression is to drive a rollerlinearly across the microfluidic channel (FIG. 5). (Lim et al., 2004)When downward pressure (501) is applied to the roller (502), a point ofcompression is created (503), which is then made to move along a PDMSchannel (504) by moving (505) the roller with a motorized actuator(506). This technique requires a large mechanical setup along with afairly large roller. Also, the roller's path is restricted linearly,which limits possible channel geometries and eliminates the possibilityof continuous or recirculating flow.

One way to create continuous flow is to use magnets and steel balls tocreate a circular compression zone that rotates along a circular pathway(FIG. 6). Yobas et al. (2008), and subsequently Du et al. (2009),present a peristaltic design that achieves compression (601) bymagnetically attracting small steel balls (602) through a thin,channeled PDMS substrate (603) backed by a rigid poly(methylmethacrylate) layer (604). The magnets (605) are made to rotate (606)using a DC motor, which causes the balls to roll in a circulartrajectory (607) along the circular PDMS channel, inducing flow from 608to 609. However, this design has many limitations. The total number ofballs that can run along a channel is limited by the minimum spacingneeded to avoid adverse magnetic interactions between the individualballs and the magnet array. Rotating the balls at higher speeds (Yobasreported maximum rotation speeds of 320 RPM) introduces the problem ofthe magnetic field not providing the requisite centripetal force,thereby allowing the balls to disengage from the device. The amount ofmagnetic restoring force provided is limited by the strength of themagnet and the separation distance (device thickness) from the balls andthe ball-to-ball spacing, and this force cannot be reliably scaledhigher without an increase in fabrication complexity via thinner devicelayers or operational complexity via the introduction of electromagnets.Using permanent magnets also defines a single compression level for thechannels, which must be tuned to provide enough compression for flow,but not enough that frictional forces hinder ball movement.Electromagnets would require ferromagnetic cores, would produce heatthat would need to be dissipated, and would require electrical powerboth to operate and to prevent passive flow or backflow through thedevice when pumping is not desired.

SUMMARY

Exemplary embodiments include a peristaltic micropump comprising one ormore conduits configured to transfer one or more pumped fluids, whereineach conduit comprises: an inlet; an outlet; and a central portionbetween the inlet and the outlet. Exemplary embodiments can alsocomprise an actuator configured to engage the central portions of theone or more conduits. In certain embodiments, the actuator is configuredto rotate about a central axis, and the central portions of the one ormore conduits form concentric partial rings about the central axis. Inparticular embodiments, the peristaltic micropump comprises at least twoconduits in fluid communication with each other, while in otherembodiments, none of the one or more conduits are in fluid communicationwith each other.

In particular embodiments, the concentric partial rings are partialcircles, while in other embodiments the concentric partial rings arenon-circular configurations. In specific embodiments, the actuatorcomprises one or more ball bearings, cylindrical rollers, or conicalrollers. In certain embodiments, the central portions of the one or moreconduits are arranged in a circumferential pattern so that the actuatorengages the central portions as the actuator rotates. In particularembodiments, each of the one or more conduits is a different length. Incertain embodiments, the ratios of the lengths of each of the one ormore conduits are a non-integer fraction. In specific embodiments, theone or more conduits are configured to form an aperiodic pattern. Inparticular embodiments, the aperiodic pattern is a Penrose Tile design.

In certain embodiments, the actuator comprises a driving element and oneor more rolling elements. In particular embodiments, the one or morerolling elements comprise one or more cylindrical rolling elements, andat least two of the cylindrical rolling elements have different lengths.In specific embodiments, the one or more rolling elements comprise oneor more conical rolling elements. In particular embodiments, the drivingelement comprises a cage configured to capture the one or more rollingelements. In specific embodiments, the one or more rolling elementscomprises one or more spherical rolling elements or cylindrical rollingelements; and the one or more rolling elements are located atsubstantially the same radius from the center of the cage.

In particular embodiments, the one or more rolling elements comprise oneor more spherical rolling elements or cylindrical rolling elements, andthe one or more rolling elements are located at different radii from thecenter of the cage. In certain embodiments, the actuator comprises arotating drive mechanism and a centering component configured to centerthe cage with respect to the rotating drive mechanism. In particularembodiments, each of the one or more rolling elements is configured torotate about an axle.

Certain embodiments further comprise one or more valves configured tocontrol flow of one or more pumped fluids in the one or more conduits.In specific embodiments, a first conduit of the one or more conduitscomprises a bypass line configured to allow fluid to flow from theoutlet of the first conduit to the inlet of the first conduit.

In particular embodiments, the one or more conduits contain at least afirst fluid and a second fluid; the one or more valves can be opened andclosed to control a flow rate of the first and second fluids duringoperation of the peristaltic micropump; and the outlets of the one ormore conduits are in fluid communication such that the first and secondfluids can be mixed in varying proportions. In specific embodiments, aconduit comprises an expanded area configured to reduce pulsatility. Inparticular embodiments, the one or more conduits are configured toreduce pulsatility. In certain embodiments, the one or more conduits areconfigured to provide sinusoidal or other output concentrationwaveforms.

Specific embodiments comprise a peristaltic microformulator comprising:a generally circumferential conduit; an actuator configured to engagethe generally circumferential conduit; one or more inlets in fluidcommunication with the generally circumferential conduit; an outlet influid communication with the generally circumferential conduit, whereinthe outlet comprises an outlet valve; and a bypass conduit coupling theoutlet and a first inlet of the one or more inlets, wherein the bypassconduit comprises a bypass valve and the first inlet comprises an inletvalve.

In certain embodiments, the generally circumferential conduit isconfigured as a circle. In particular embodiments, the generallycircumferential conduit is configured as a circle, triangle, square,pentagon, hexagon, heptagon, or octagon. In certain embodiments, each ofthe one or more inlets comprises a valve; the one or more inlets areconfigured to deliver at least a first fluid and a second fluid to thegenerally circumferential conduit; and the valves of the one or moreinlets can be opened and closed to control the amount of the first andsecond fluid that is pumped through the outlet during operation.

Particular embodiments include a peristaltic micropump comprising: aconduit configured to transfer a pumped fluid; and an actuatorconfigured to rotate about a central axis, wherein: the actuatorcomprises a rolling element and a driving element; the rolling elementis disposed between the conduit and the driving element; and the drivingelement and the conduit have a coefficient of friction that issubstantially similar. In certain embodiments, the driving element andthe conduit are comprised of a flexible polymeric compound. Inparticular embodiments, the driving element and the conduit arecomprised of polydimethylsiloxane (PDMS).

Specific embodiments include a peristaltic micropump comprising: aconduit configured to transfer a pumped fluid; and an actuatorconfigured to rotate about a central axis, wherein: the actuatorcomprises a rolling element and a driving element; the rolling elementis disposed between the conduit and the driving element; and the drivingelement and the conduit have coefficients of both elasticity andfriction that are substantially similar. In particular embodiments, thedriving element and the conduit are comprised of a flexible polymericcompound. In certain embodiments, the driving element and the conduitare comprised of polydimethylsiloxane (PDMS).

Specific embodiments include a peristaltic micropump comprising: acircumferential conduit; an external conduit comprising one or morevalves, wherein the one or more valves are in fluid communication withthe circumferential conduit; and a rotating actuator comprising one ormore rolling elements configured to engage the circumferential conduitand actuate the one or more valves, wherein the one or more valves areconfigured to control a fluid flow in the external conduit. In certainembodiments, the circumferential conduit comprises one or more ports influid communication with the one or more valves, and wherein the spacingof the ports on the circumferential conduit can be used to control thefluid flow in the external conduit.

In particular embodiments, the one or more valves are normally closed,and a valve is opened when a rolling element engages a port on thecircumferential conduit. In specific embodiments, during use theactuator rotates at a constant rotational speed and the fluid flow inthe external conduit varies over time.

Particular embodiments include a microvalve comprising: a first conduitcomprising an inlet and an outlet; an actuator configured to rotateabout a central axis; and one or more rolling elements coupled to theactuator, wherein the one or more rolling elements are configured torotate about the central axis at a first radius, wherein: a firstportion of the first conduit is located at the first radius from thecentral axis; and a second portion of the first conduit is located at asecond radius from the central axis.

In specific embodiments, the actuator comprises a driving element, therolling element is disposed between the first conduit and the drivingelement, and the driving element and the first conduit have acoefficient of friction that is substantially similar. In particularembodiments, the driving element and the conduit are comprised of aflexible polymeric compound.

In certain embodiments, the actuator comprises a driving element; therolling element is disposed between the first conduit and the drivingelement; and the driving element and the first conduit have acoefficient of elasticity that is substantially similar. In particularembodiments, each of the one or more rolling elements is configured torotate about an axle. In certain embodiments, the one or more conduitsare configured to provide sinusoidal or other output concentrationwaveforms. In certain embodiments, the one or more conduits areconfigured to provide droplets of a first fluid encased in a secondfluid. In particular embodiments, during operation the one or morerolling elements engage the first portion of the first conduit as therolling element rotates about the central axis. In specific embodiments,the one or more rolling elements are configured to occlude a fluid flowbetween the inlet and the outlet of the first conduit when the one ormore rolling elements engage the first portion of the conduit.Particular embodiments comprise a second conduit extending between aninlet and an outlet, wherein a first portion of the second conduit islocated at the first radius from the central axis; and a second portionof the second conduit is located at a second radius from the centralaxis.

In certain embodiments, the first and second conduits comprise multipleportions at the first radius from the central axis and multiple portionsat the second radius from the central axis. In specific embodiments, theoutlet of the first conduit and the outlet of the second conduit are influid communication. In particular embodiments, a rotation of theactuator controls a first fluid flow in the first conduit and a secondfluid flow in the second conduit. In certain embodiments, the firstconduit and the second conduit each comprise multiple portions at thefirst radius from the central axis. In particular embodiments, therolling element is a ball bearing, a cylindrical roller, or a conicalroller. In particular embodiments, the driving element comprises a cageconfigured to capture the one or more rolling elements.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate one or more embodiments of theinvention and, together with the written description, serve to explainthe principles of the invention. Wherever possible, the same referencenumbers are used throughout the drawings to refer to the same or likeelements of an embodiment.

FIG. 1 shows schematically the classical, macroscopic peristaltic pump.

FIGS. 2A-2B show schematically two implementations of peristalticpumping in microfluidic devices, as described in Darby et al. (2010).

FIG. 3 show schematically two implementation of peristaltic pumping, asdescribed in Gu et al. (2004) and Takayama et al. (2010).

FIG. 4 shows schematically an implementation of peristaltic pumping, asdescribed in Chou et al. (2001).

FIG. 5 shows schematically another means of inducing peristalticcompression, as described in Lim et al. (2004).

FIG. 6 shows schematically a means of creating continuous flow by usingmagnets and steel balls to create a circular compression zone thatrotates along a circular pathway, as described in Yobas et al. (2008)and Du et al. (2009).

FIG. 7 shows schematically a peristaltic micropump that comprises acircumferential conduit or channel with an inlet, an outlet, and aseries of rolling elements driven by a motorized hub, according toexemplary embodiments of the invention.

FIG. 8 shows schematically a means of causing rolling elements to rotateby turning a hard disk pressed against steel balls positioned over PDMSchannels, according to certain embodiments of the invention.

FIG. 9 shows schematically that a series of balls could be pushedsimultaneously by capturing each ball in a circular array of sockets,i.e., a cage., according to certain embodiments of the invention.

FIG. 10 shows schematically the use of a deformable rotating disk todrive rolling elements, according to certain embodiments of theinvention.

FIG. 11 shows schematically the use of deformable PDMS or anotherelastomer disk to provide the force that causes the array of balls torotate, according to certain embodiments of the invention.

FIG. 12 shows schematically a thrust bearing that compresses themicrofluidic channels, according to certain embodiments of theinvention.

FIG. 13 shows schematically exemplary embodiments of the rotary planarperistaltic micropump (RPPM).

FIG. 14 shows schematically the coupler comprising a shaft and hub,according to one embodiment of the invention.

FIG. 15 shows schematically a configuration of the base piece, accordingto one embodiment of the invention.

FIG. 16 shows schematically the microfluidic components fabricated usingsoft lithographic techniques and replica molding, according to oneembodiment of the invention.

FIGS. 17A-17B show schematically a roller thrust bearing, in certainembodiments of the invention.

FIG. 18A shows schematically a multipath-design mixer, according to oneembodiment of the invention.

FIG. 18B is a table showing one exemplary configuration of the valvesfor the multipath-design mixer of FIG. 18A.

FIG. 19 shows schematically an aperiodic pattern of splitting andrecombining flow streams in a circular Penrose design, according to oneembodiment of the invention.

FIG. 20 shows schematically a rotary microformulator, according to oneembodiment of the invention.

FIG. 21 shows schematically the use of recirculating fluid input holderchannels that remain in contact with the rollers of the RPPM formetering the addition of a solution to the mixer, according to oneembodiment of the invention.

FIG. 22 shows schematically a fluid input method using a valve with aninput and output channel on either side, according to one embodiment ofthe invention.

FIG. 23 shows schematically a radial arrangement of fluid inputs alongthe perimeter of the circular channel, according to one embodiment ofthe invention.

FIG. 24 shows schematically an implementation of valve protection for avalve outside of the main flow loop, according to one embodiment of theinvention.

FIG. 25 shows schematically an implementation for a valved pump channel,in one embodiment of the invention.

FIG. 26 shows schematically an implementation of rollers or bearingsdesigned in conjunction with external structures such as closed channelsthat, for example, can be used to control metering, according to oneembodiment of the invention.

FIG. 27 and FIG. 28 illustrate schematically the first implementation ofthe RPPM.

FIG. 29 and FIG. 30 illustrate schematically a simple rotary pump and aPenrose mixer, respectively, in a recent implementation of the RPPM.

FIG. 31 shows schematically a configuration of the RPPM that providessupport for separate, simultaneous pumping for multiple externaldevices, according to one embodiment of the invention.

FIGS. 32A-32C show schematically variations of a microfluidic designhaving multiple concentric channels, according to certain embodiments ofthe invention.

FIGS. 33A and 33B show schematically two embodiments of the inventionwith different microfluidic configurations for a multiple channel devicethat allows crosstalk between channels to allow, for example, mixing.

FIGS. 34A and 34B show schematically the use of conical and cylindricalrollers for a rotary pump, according to certain embodiments of theinvention.

FIGS. 35A-35E show schematically a variety of cage designs for customthrust bearings, according to certain embodiments of the invention.

FIGS. 36A-36C illustrate schematically the principle of operation and adiagram of a rotary planar valve (RPV) microvalve, according to oneembodiment of the invention.

FIGS. 37A-37C show schematically the concept, design, and functioning ofa pulse-width modulation RPV waveform generator, according to oneembodiment of the invention.

FIGS. 38A-38D show schematically the design and operation of a variableflow rate RPPM, according to one embodiment of the invention.

FIGS. 39A-39D illustrate schematically a pulse-regulating device,according to one embodiment of the invention.

FIG. 40A shows schematically an RPPM configured as a two- or three-phasedroplet generator, according to one embodiment of the invention.

FIGS. 40B-40C illustrate schematically an RPPM and RPV system that canact as both a fluid multiplexer and demultiplexer and the summed flow ofthe system, according to one embodiment of the invention.

FIG. 41A shows schematically a profile view of a peristalsis system inmicrofluidics, according to one embodiment of the invention.

FIG. 41B shows schematically a single-channel RPPM design and afive-channel configuration, according to certain embodiments of theinvention.

FIGS. 41C-41E show schematically three views of one embodiment of anRPPM system.

FIGS. 42A-42B show schematically a compact RPPM and its physicalimplementation, respectively, according to one embodiment of theinvention.

FIGS. 42C-42D show schematically the unassembled parts of an RPPM andthe assembled device, respectively, according to another embodiment ofthe invention.

FIGS. 43A-43C show schematically a design for a multi-pump array,according to one embodiment of the invention.

FIG. 44 presents the linear relationship between flow rate and motorspeed exhibited by one embodiment of the invention.

FIGS. 45A-45C show schematically and with kymographs how two RPPMs maybe arranged to provide two-dimensional control of particles in amicrofluidic device, according to one embodiment of the invention.

FIGS. 46A-46C illustrate schematically the design and operation of anRPPM- and RPV-driven batch mode microformulator, according to oneembodiment of the invention.

FIG. 47 illustrates schematically a high-density array of microfluidicsingle-cell yeast traps, according to one embodiment of the invention.

FIGS. 48A-48F illustrate the steps toward implementation of theembodiment of FIG. 47.

FIG. 49A shows schematically the utilization of rotary thrust ballbearings as planar valves to drive serial switching between threedifferent flow configurations, according to one embodiment of theinvention.

FIG. 49B shows schematically a rolling element configuration that allowsindependent perfusion of the nanobioreactors in FIG. 49A, according toone embodiment of the invention.

FIGS. 49C-49D show schematically the subsequent clockwise rotation ofthe rolling element cage of the embodiment shown in FIG. 49B to the nextand last unique states, respectively.

FIG. 50 illustrates schematically the design of an RPPM-driven andQuake-style valve-controlled batch mode microformulator, according toone embodiment of the invention.

FIGS. 51A-51D show schematically and in images the concept, design, andoperation of a Quantum Dot Hybridzer, according to one embodiment of theinvention.

FIG. 52A shows schematically the Preparation Mode of a well-plate assaysupported by an integrated RPPM-RPV device, according to one embodimentof the invention.

FIGS. 52B-52C show schematically alternative embodiments of the AssayMode of the well plate of FIG. 52A.

FIG. 53 shows schematically how the well-plate controllers of FIGS.52A-52C could be connected to a 12-well plate, according to oneembodiment of the invention.

FIGS. 54A-54D illustrate schematically an RPPM device that maintains aconstant flow rate without pulsatility, according to one embodiment ofthe invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Referring now to FIG. 7, a peristaltic micropump 700 comprises acircumferential conduit or channel (701) with an inlet (705), an outlet(706) and a series of rolling elements (702) (e.g., roller bearings),driven by a motorized hub (704). During operation, rolling elements(702) engage and compress a circumferential channel (701) and pump afluid from inlet (705) to outlet (706). In the power-off mode when thepump is not operating, one or more rolling elements prevent passiveforward or reverse flow through the device. In certain embodiments, thecircumferential channel (701) may be formed as a circle, and in otherembodiments circumferential channel (701) may be formed as a polygon(e.g., a triangle, square, pentagon, hexagon, heptagon, octagon, etc.).It is understood that the circular or polygonal shape of circumferentialchannel (701) is used in general terms and describes the shape ofcircumferential channel (701) if circumferential channel (701) extendedthrough the space between inlet (705) and outlet (706).

During operation of pump 700, a z-axis stage control device can be usedfor variable compression as well as continuous flow capability. Onelimitation of this approach is the fabrication complexity and cost ofthe mechanical roller mechanism. In FIGS. 5 and 7, the rolling elements(502 and 702) are moved by a mechanical connection to the axle (506 and703) that provides either translation (505) or rotation (704). In FIG.6, the ball is moved by means of a rotating magnetic field gradient.FIG. 8 shows how the rolling balls could be caused to rotate by turninga hard disk (801) that is pressed (802) against steel balls (803)positioned over PDMS channels (804). This configuration, however, lacksan alignment system, which will eventually lead to the balls disengagingfrom the channel-disk system, and the differences in the coefficients ofsliding friction and elasticity between the PDMS, the balls, and thehard plate could lead to the plate slipping against the balls, whichthen would not rotate or roll.

FIG. 9 shows that a series of balls (901) could be pushed simultaneouslyby capturing each ball in a circular array of sockets (902) (a “cage”).This introduces a strict alignment system; however, it also couldproduce substantial sliding friction. Since the balls are captured bycontact (903 and 904) with the sides of the cage (903 and 904) and thetop (905), the sliding friction between the ball and the cage at thesepoints opposes the balls' tendency to roll (906), introducing thepossibility of the balls sliding across the PDMS surface rather thanrolling. Because of this friction, the torque required for rotating asliding ball and cage system is much greater than that of the rollingball and cage system. Varying the cage's size introduces a trade-offbetween the ability of the ball to roll and the chances of a balldisengaging from the cage.

Embodiments of the present invention comprise numerous features thatprovide benefits over existing configurations. For example, certainembodiments of the present invention include the use of a deformablerotating disk to drive rolling elements, (e.g., steel balls in certainembodiments), as shown in FIG. 10. By using PDMS or another elastomerfor both this driving disk (1001) and the microfluidic device (1002),the elastic deformations above and below the steel balls (1003) arematched, drastically reducing the incidence of sliding friction. Thearray of balls is kept in alignment by a cage (1101) with a circulararray of openings (1102) for the balls (1103) (FIG. 11). The cage isfree-floating and therefore does not provide the force that causes thearray of balls to rotate. This force is provided instead by thedeformable PDMS or other elastomer disk (1104), which results in theballs moving with rolling (1105) rather than sliding friction. Aconvenient analogy of the two means to roll the balls, i.e., with arigid or deformable disk, is to consider rolling an apple between a bookand the palm of the hand, versus between two hands. In the former case,the book is likely to slide against the apple due to the elastic forcesprovided by the lower hand and the smaller sliding friction between thebook and the apple, as compared to that between the apple and the hand.In the latter case, the elastic deformations of both hands are matchedto each other and the apple rolls easily. With the deformable drivingdisk, the balls actually drive the cage, and since little force isapplied to the cage, little work is required to rotate it and hencethere is little power dissipation associated with the cage. This systemcan in fact be constructed in the same manner as a thrust bearing. Theballs act as bearings between the PDMS disk (1104) and channeled device(1106). The upper PDMS disk drives the thrust bearing over a circularpath above the channels in the lower PDMS device. The cage simply keepsthe balls aligned, both radially and tangentially.

In certain embodiments of the present invention, the rotary planarperistaltic micropump (RPPM) uses a thrust bearing (FIG. 12) to compressmicrofluidic channels. As an upper disk is rotated, the balls (1201)within the thrust bearing roll to create the moving compressional wavethat drives fluid through the underlying channels that could becontained within the lower element (1204) were it fabricated from anelastomeric material. The cage (1202) of the thrust bearing confines theballs as they roll, but does not provide enough friction to causesliding. This is another advantage of the RPPM. Many previousperistaltic pumps, including that of Darby et al., involve significantfrictional forces caused by the dragging of the compressing object alongthe surface, an issue that the matched rolling action of the RPPM'sthrust bearing and the two matched deformable surfaces avoids. Withrolling friction, the wear on the PDMS pieces, particularly thechanneled device, is greatly reduced as compared to a design withsliding friction, allowing for prolonged use of the device. A standardthrust bearing also contains two inelastic washers (1203 and 1204),usually metallic in nature, that sit above and below the ball (1201) andcage assembly (1202). In exemplary embodiments of the RPPM design (FIG.13), these washers are made of PDMS, with the bottom washer comprisingthe channeled PDMS microfluidic device (1301), and the top washer beingthe aforementioned disk (1302) that drives the rotation. The bearing(1303) is turned by the frictional forces acted on it by 1302, which isattached to a coupler (1304) that is turned by a stepper motor (1305).In specific embodiments, the coupler (1304) may be custom-machined metalor plastic.

In an ideal system with only rolling friction, the bearing cage turns atexactly half the rate of the motor. The coupler (1304) contains a shaft(1306) that provides axial registration for the PDMS disk (1302), thethrust bearing (1303), and PDMS device (1301). The shaft terminateswithin a circular opening at the center of a disk (1307) that serves asthe ultimate base of the entire device. In certain embodiments, the disk(1307) may be formed from polycarbonate or other material. Along withthe center hole (1308), disk (1307) contains tapped holes (1309 and1310) along the edge that correspond to openings (1311 and 1312) on themounting of the stepper motor. Altogether, the PDMS pieces, the steppermotor, the metal or plastic coupler, the polycarbonate base piece, andthe mounting screws (1313 and 1314) comprise an exemplary embodiment ofan RPPM system.

In the embodiment shown in FIG. 14, the coupler 1304 comprises a shaft(1401) with a diameter just under the inner diameter of the desiredbearing and a hub (1404) at least as large as the outer diameter of thebearing. The length of the shaft (1402) determines the total allowablethickness of the PDMS washer, bearing, and PDMS channels. Taking intoconsideration these parameters, an additional distance (e.g., 2-5 mm) isneeded so that the shaft extends into the polycarbonate base. Thediameter of this shaft (1403) is determined by the inner diameter of thebearing used. The shoulder on the coupler is of a diameter (1404) thatis larger than the bearing outer diameter. A center hole (1405) in thecoupler provides a connection to the motor shaft, and a tapped hole(1406) and set screw (1407) secure the coupler to the motor.

The base piece (FIG. 15) shown here as a circular disk (1501) has acentered hole (1502) that is just larger than the metal or plasticshaft. Two threaded holes (1503 and 1504) match the holes on the motormount (1311 and 1312), and provide and control compression to thedevice. Depending on the stability and configuration of the mount andmotor used, this base piece may contain, for example, up to 4 mountingholes. Other configurations of the base, motor mount, and drivecomponents are also possible in other exemplary embodiments.

The fabrication of the microfluidic device (FIG. 16) can be accomplishedwith soft lithographic techniques and replica molding. In certainembodiments, the master mold can be created in a photolithographicprocess that uses a silicon wafer and SU-8 negative photoresist toproduce a flat silicon base with raised patterned structures composed ofcross-linked photoresist. The positive-relief pattern is created byshining UV light through a patterned mask onto a thin layer of SU-8negative photoresist residing on the silicon wafer. Restricted by theusage of a thrust bearing, the microfluidic design requires a circularcompression zone. The size of these radially arranged channels isdetermined by the size of the thrust bearing. Exemplary embodimentscontain multiple concentric channels (1601) to ensure that a slightlyoff-center placement of the thrust bearing will still cause flow, or toallow increased flow rates for a given rotational velocity.

In one exemplary embodiment, to create the microfluidic device, a thinlayer of PDMS (1602) (e.g., 100 μm in certain exemplary embodiments) isspun onto the silicon master. Pre-cured tubing-support cubes of PDMS(1603 and 1604) are then placed over the input and output holes of themaster and the entire device is allowed to cure. The cured PDMS is thencarefully removed from the wafer and I/O holes (1605 and 1606) arepunched through the PDMS cubes. The punched device is then plasma bondedto another thin layer of cured PDMS (1607). Lastly, a hole for the metalor plastic shaft (1608) is punched at the center of the bonded device.

Altogether, the components described above comprise an exemplaryembodiment of a rotary planar peristaltic micropump. Assemblyinstructions for the exemplary embodiment described above follow. It isunderstood that the following assembly description is merely one exampleof assembly, and that other suitable alternatives may be substituted forcertain components or steps. For example, the retainers may beconfigured differently than shown and described.

To assemble the pump, the coupler (1304) is slid onto the motor's (1305)shaft (1315) and secured using a retainer (1316) (e.g., a set screw).The PDMS washer (1302) can then be added onto the shaft of the coupler(1304), followed by the thrust bearing (1303), followed by the channeledPDMS device (1301). The end of the coupler's shaft (1306) fits into thecenter hole (1308) of the base piece (1307). The pieces can then besecured together with adjustable retainers (e.g., machine screws) (1313and 1314) passing through the motor mount (1311 and 1312) andterminating in the tapped holes (1309 and 1310) in the polycarbonatebase (1307). Loosening or tightening the adjustable retainers (1313 and1314) controls the amount of compression felt by the channels.

Exemplary embodiments of the present invention offer numerous advantagesover other peristaltic pumps used in microfluidic devices. Many currentmicrofluidic systems are driven by computerized mechanical pumps, forexample, linear syringe pumps, or by banks of computer-controlledsolenoids to deliver pressure to selected control channels. Compared tothese expensive pumps, which require a computer or microprocessor andeither complex mechanical actuators or expensive valve banks and apressure regulator, exemplary embodiments of the present inventionrequire a simple motor to turn the assembled device. In contrast to manyperistaltic pumps in microfluidic devices, when the motor drivingvarious embodiments of the present invention is turned off, regions ofcompression remain in the channels and block passive forward or reverseflow through the pump. Also, with peristalsis, the system does notdirectly pump from a reservoir, thus allowing for the possibility of arecirculating setup that addresses the problem of a finite reservoir andpermits prolonged experimentation that requires little to nomaintenance.

Exemplary embodiments of the present microfluidic peristaltic pump maybe used for microfluidic mixing. By reconfiguring the channeled PDMSdevice and replacing the ball thrust bearing (FIG. 12) with a rollerthrust bearing (schematics shown in FIGS. 17A and 17B), many differentmixer designs can be fabricated. The roller thrust bearing features acage (1701 and 1705) and rolling elements configured as cylindricalrollers (1702 and 1706) coupled, for example, to the cage via pins (1703and 1707) that pass through a central hole (1704 and 1708) in each ofthe cylindrical rollers. FIG. 17B shows rollers of variable length andplacement (1709-1711), which prove useful in mixing applications.

FIG. 18A shows a multipath-design mixer, with three channels (1801-1803)with a path length ratio of roughly 1:2:3. A series of 13 valves(depicted by rectangles, e.g., 1804) controls each of the six modes forthe pump. One exemplary configuration of the valves for each mode isshown in FIG. 18B (Table 1). 1805-1807 are three possible inputs forthis design, and 1808-1810 are the three possible outputs. The nodesdenoted by asterisks (1811 and 1812) are connected via tubing and usedonly during the series recirculation mode. This design would most likelyutilize the roller thrust bearing shown in FIG. 17A. A second possiblemixer design would use a pattern derived from Roger Penrose's aperiodicset of thick and thin rhombus tiles. This design, shown in FIG. 19, hasmultiple inputs (1901-1903) to allow for parallel loading of mixingcomponents, and a circular Penrose design (1904) that is compressed by aroller bearing as shown in FIG. 17A or 17B. A series of valves similarto those used in FIG. 18 could also be incorporated in this design forgreater control of mixing modes. Using the variable length rollers(1709-1711) of FIG. 17B along with the aperiodic pattern of FIG. 19 cancreate a unique scenario of splitting and recombining flow streams thatwill increase mixing efficiency. The long rollers would ensure that thesolution had a net tangential flow around the pump and was completelyexpelled from the pump at the end of the mixing process, and the shortrollers would provide a local circulation that would enhance mixingefficiency. Combining either of the mixing designs with a valve bankwould also allow for the fabrication of a rotary reagent formulator.

It is important in many biological and chemical research projects to beable to produce solutions that contain a large number of differentchemical substances at differing concentrations. Historically,preparation of these solutions would be done by separate weighing,volume measurements, serial dilutions, and mixing. More recently, thisprocess has been automated by the use of either manual pipetting withcontrolled dispensing, or by acoustic droplet generators.

Two main types of microformulator devices have been created. One type isa junction at which multiple input channels of fluid are combined into asingle channel and then mixed, either by lateral diffusion over thelength of a long channel, or by other mixing approaches, such as chaoticmixers or three-dimensional mixers. The concentration of each fluid canbe controlled by the input velocity of their respective channels.Junction mixers are fast but are accurate for only two different fluidinputs. The second type is in the style of the Hansen et al. (2004)device, which at present represents the state of the art in microfluidicformulators. Hansen devised a microfluidic microformulator that utilizeda large number of pneumatically operated valves and pumps to mixpicoliter volumes from 32 reservoirs that could be loaded with differentchemical solutions. In this type of microformulator, fluids frommultiple input channels are serially loaded into a mixer system, theoutput of which is then pumped from the device. The Hansen-stylemicroformulator creates accurate mixtures, although it is slow due toits serial nature. Other limitations of this system include the largenumber of valves, the low volume of the device, and the time required toproduce and mix a microliter of solution.

Exemplary embodiments of the invention using a rotary planar peristalticmicropump can be extended to create a microformulator of a differentdesign: a system that can rapidly combine, mix, and dispense a solutionthat contains an arbitrary number of solutions combined at controlledvolumes to achieve the desired concentration of each component.

The rotary planar peristaltic micropump (RPPM) (FIGS. 13-16) can becombined with microfluidic channels and a loading system to form amicroformulator, identified as a rotary microformulator. The use of theRPPM as the driver of a microformulator is an improvement of currentmicroformulators, in part due to its speed, versatility, accuracy, andsmall size.

The functionality of the rotary microformulator (FIG. 20) isaccomplished with a circular channel (2001) containing radially arrangedinputs (2002). The RPPM compresses this channel to cause fluid flow. Therotation of the bearings (2006) or rollers of the RPPM over the flowchannel (2007) causes fluid to be pumped through the channel. Thisdriving action of the bearings allows for precise control over the flowrate of the fluid, facilitating precise metering of both input andoutput solutions. The RPPM also allows for high flow rates compared tothose of alternative methods, allowing for fast mixing of larger volumesof liquid.

Valves are used to control the flow configuration of the rotaryformulator. When the valve on the connecting or bypass channel (2005) isclosed and the others are open, fluid flows from the input channel(2007) to the output channel (2008). When the input valve (2004) and theoutput valve (2003) are closed and the connecting valve (2005) is open,the main channel forms a closed path through which the RPPM can inducecontinuous recirculatory flow. The recirculation of flow allows forrapid solution mixing. Multiple input solutions can be loaded into thechannel either in flow configurations using methods involving suchstructures as multiplexers or in radially arranged inputs (2002).

Alternatively, the device can be used to mix an arbitrary number ofsolutions in a strictly linear path as opposed to a recirculating loop.The RPPM can draw fluid in from a multiplexer or radially positionedinputs, which lets various solutions into the mixture in quantitiescontrolled by varying the time and frequency that the channel to eachreservoir of solution is open. As the pump runs, it draws in eachsolution in proportion to the time that each reservoir channel is open.To facilitate the mixing process, the opening of the reservoirs isalternated so that the distance that each bolus of solution must diffuseis minimized. Once the correct ratios of solutions are drawn from theirrespective reservoirs, the mixture is pumped through a long, meanderingpathway so that when the fluid is pumped out of the device, it is fullymixed. Using such a device, the composition of the mixture can bedynamically varied (i.e., sinusoidal variation of certain solutions)simply by varying the solution inputs. Such a device would beadvantageous because the rotary planar peristaltic micropump eliminatesthe need for multiple pumps, while still maintaining a high pumpingrate.

An almost sinusoidal concentration of an output mixture of two solutionsis accomplished with two converging channels whose widths vary accordingto sinusoidal relationships. The flow rate of the channels produced bythe rotating bearings or rollers of the RPPM varies according to thewidths, causing the converged mixture to have sinusoidal concentrationsover time.

Solution input into the device is accomplished by connecting channels tothe main fluid flow channel. Valves are used to control the opening andclosing of these input channels. Implementations of this general inputstructure can be accomplished in a number of ways. The simplest approachthat is sufficient for serial output of mixtures is the use of a singlemultiplexer that connects to the input of the device, functioningsimilarly to the Hansen et al. (2004) formulator. The bearings rotate acertain amount to load solutions from the multiplexer serially toachieve the desired mixture. A multiplexer can also be used along theperimeter of the circle to allow for very rapid input. In thisconfiguration, the multiplexer loads channels connected to the mainfluid flow path in defined amounts. As the RPPM rotates, the fluid isdrawn in.

Another method for fluid input, shown in FIG. 21, is through the use ofrecirculating fluid input holder channels (2103) that remain in contactwith the rollers (2104) of the RPPM. The fluid input holder channel(2103) is connected to the main flow channel (2101) through a valvedangled channel (2102). When a single path is formed between the fluidinput supply (2108) and the main fluid channel (2102) by closing onlyone valve (2106), the roller meters solution into the mixture. When thepath is closed from the fluid input supply (2108) to the fluid channel(2101) by closing the connecting valve (2105) and the supply valve(2107), the fluid in the input holder (2103) simply recirculates alongthe closed path. Hence the roller is continuously moving fluid in aperistaltic fashion, and the selection of which valves are open orclosed determines whether injection or recirculation is recurring, butin no case are large pressures developed by having a peristaltic pumpattempt to move fluid past a closed valve.

An additional fluid input method, shown in FIG. 22, uses a valve (2204)with an input (2202) and output (2201) channel on either side. As aroller (2205) of the RPPM rolls over the valve (2204) and past it, fluidin the main channel (2203) is directed out of the output channel (2201)and fluid from the input channel (2202) is directed into the mixer atmain channel (2203).

Alternatively, as shown in FIG. 23, the fluid inputs can be arrangedradially along the perimeter of the circular channel (2303), each inlet(2301) being immediately preceded by an outlet (2302) and a valve(2304). To load fluid, the device is initially loaded with an arbitrarysolution, such as water. As a roller (2305) moves across the valve, thevalve blocks the main channel and forces fluid out through the outlet(2302). A vacuum is then formed between the PDMS and the substrate, sowhen the rollers move past the solution inlet (2301), fluid is drawn in.Using this method, the volume of each solution input can be varied byactuating the valves in a certain sequence and precisely varying therotation of the bearings.

The use of pneumatic microfluidic valves with the rotary microformulatorcan be accomplished with a multi-layer PDMS device. In the multiplelayers the control channels of the valves are protected such thatcompression of the closed valve does not fully close the controlchannel. This allows a channel to be compressed by the RPPM despitebeing closed.

An implementation of this valve protection for a valve outside of themain flow loop is shown in FIG. 24. As rollers depress the pump channel(2407), the valve channel cover (2406) is also depressed, thereforeprotecting the valved channel (2405). The four-layer PDMS structureshown consists of a pump layer (2401), a valved channel layer (2402), acontrol layer (2403), and a base layer (2408). The channel in thecontrol layer (2403) contains the control channel (2404), which expandswith air to close the valved channel (2405). The pump channel (2407) isin the same layer as the valved channel cover (2406).

An implementation for a valved pump channel is shown in FIG. 25. Whetheror not the main flow channel (2505) in the pump layer (2501) iscompressed by the control valve (2504), there remains sufficient spacein the control valve (2504) in the control layer (2502) for properfunctionality, regardless of the RPPM state. The base of the controlvalve (2504) is provided by the base layer (2503).

The rollers or bearings can be designed in conjunction with externalstructures, such as closed channels, to provide functionality inaddition to the pumping. This can be used, for example, to controlmetering. FIG. 26 shows an implementation of this hardwiredfunctionality. As the rollers of the RPPM (2602) rotate around the flowchannel (2601), they sequentially depress the closed valves (2605, 2604,2603). The compression of the closed valves on one side by the rollers(2602) allows the closed valves to act as a pneumatically actuatedperistaltic pump on a different channel (2606). Using this technique, anentire sequence of fluid flow handling events can be encoded in therotation of the RPPM. This allows for complex devices to be controlledby a simple motor running at an arbitrary rate.

A mixer driven by an RPPM can be useful in experiments requiring asteady flow of a precise combination of solution components, even whenthose components must be dynamically and precisely varied. Previousmixers have used either a single pneumatically actuated microfluidicpump to draw fluid from different reservoirs, which cannot handle higherflow rates, or individual syringe pumps for each input solution, whichare costly and complicated. Our device eliminates both of theselimitations by using a single high flow rate peristaltic pump to draweach solution, eliminating the expense of multiple pumps. In addition,the use of an easily controlled motor and the lack of pressure-actuatedvalves allow the device to remain compact and suitable for on-site orlow-resource settings. The device can be used to expand the repertoireof fluid flow operations that point-of-care microfluidic devices canperform.

FIGS. 27 and 28 illustrate the first implementation of the RPPM, andFIGS. 29 and 30 show a more recent implementation, with FIG. 29 showinga simple rotary pump, and FIG. 30 showing a Penrose mixer.

Referring now to the exemplary embodiment shown in FIG. 31, themicrofluidic portion of the RPPM can be configured to provide supportfor separate, but simultaneous pumping for multiple external devices.Fluid can be drawn in through the inlets or inputs (3101-3104) andpumped through multiple concentric channels (3109) to the outlets oroutputs (3105-3108). The multiple concentric channels (3109) arearranged in four channel sections that spatially and fluidicallyseparated from one another. The angular extent of the multipleconcentric channels (3109) in each section can be different to providedifferent pumping rates or duty cycles, depending upon the configurationof rollers (FIGS. 17A and 17B).

In the exemplary embodiment of FIG. 32A, a microfluidic design is shownthat could be used with the RPPM to pump a fluid from an input node(3201) to an output node (3202). This embodiment has multiple concentricchannels (3203) fluidically connected to the input node (3201) and theoutput node (3202) to increase flow rate and protect against channelblockage.

The embodiment illustrated in FIG. 32B shows a slight variation of 32A,with each of the concentric channels (3206) fluidically connecteddirectly to the input node (3204) and the output node (3205).

The embodiment of FIG. 32C provides a microfluidic design that could beused to pump several different fluids simultaneously and withoutcrosstalk. Each of the inputs (3207-3210) has a corresponding output(3211-3214). For example, the input node (3207) has a correspondingoutput node (3211); the input node (3208) has a corresponding outputnode (3212), and so on. In the embodiment shown in FIG. 32C, eachconcentric channel is fluidically and directly connected to an inputnode and its corresponding output node. In function, this embodiment issimilar to the one shown in FIG. 31.

The embodiments shown in FIGS. 33A and 33B provide two differentmicrofluidic configurations for a multiple channel device that allowscrosstalk between channels, for example, to allow mixing. As shown inFIG. 33A, the multiple concentric channels are arranged in six channelsections (3303) with a first multiple channel section and a lastmultiple channel section. The six channel sections (3303) are spatiallyand fluidically connected to one another through the concentric channelportion (3304 or 3305) except that the first and last multiple channelsections are spatially and fluidically separated from one another. Thefirst multiple channel section and the last multiple channel section arefluidically connected to an input node (3301) and an output node (3302),respectively. In FIG. 33A, fluid is drawn in through the input node(3301), allowed to split into multiple channel sections (3303), and thenforced to recombine as the channels collapse to the single channelportion (3304) toward the center of the design. A flow is then allowedto split again and recombine at the single channel portion (3305) towardthe outer rim of the design. During operation, the process can berepeated twice more until the fluid exits at the output node (33021).The differences in path length result in longitudinal mixing.

As shown in FIG. 33B, the multiple concentric channels are arranged infive channel sections (3308) with a first multiple channel section and alast multiple channel section. The five channel sections (3308) arespatially and fluidically connected to one another through a concentricchannel portion (3309) except that the first multiple channel sectionand the last multiple channel section are spatially and fluidicallyseparated from one another. The first multiple channel section and thelast multiple channel section are fluidically connected to an input node(3306) and an output node (3307), respectively. In the embodiment ofFIG. 33B, the splitting of the flow can occur in each of the fivechannel sections (3308) and recombination of the flow can occur in themiddle of the concentric channel portion (3309). Fluid enters at theinput node (3300 and exits at the output node (3307).

The embodiment of FIG. 34A shows a schematic of conical (3401) andcylindrical (3405) rollers between two layers of PDMS (3402 and 3403,3406 and 3407). During operation, these rollers can be depressed so thatthey compress their respective microfluidic channels (3404 and 3408).

The embodiment shown in FIG. 34B illustrates some of the advantages ofusing conical rollers for a rotary pump. A conical roller (3409) rollsin a circle (3410) because of the differences in radii at its endpoints. A thrust bearing using conical rollers also has the advantage ofbeing self-centering when depressed by the coupler and PDMS washersystem. On the other hand, cylindrical rollers (3411) roll in a straightline (3412), implying that, when included in a thrust bearing, arestoring force on its outer edge is required for rotary motion, andthat there can be differential slippage along the length of the rollerif it is forced to roll in a circle.

The embodiments illustrated in FIG. 35 show a variety of cage designsfor custom thrust bearings. The physical cage assemblies for the designsare denoted as 3501, 3503, 3506, 3508, and 3511.

The embodiments of FIGS. 35A and 35B show designs that would containrollers. The equivalently sized and spaced openings (3502) in FIG. 35Awould accommodate 20 rollers of equal length, whereas the smalleropenings (3505) in FIG. 35B would accommodate shorter rollers in astaggered fashion. Longer rollers (3504) are inserted at regularintervals to push flow along.

FIGS. 35C, 35D, and 35E show embodiments that can contain sphericalballs as the rolling elements. FIG. 35C shows an embodiment with a cageconfiguration for a standard ball thrust bearing, with openings atregular intervals (3507) for balls. The embodiment of FIG. 35D has astaggered configuration of openings (3509), akin to that shown in FIG.35B. Three openings (3510), spanning from the inner to the outer radius,mimic the flushing action of the longer rollers. FIG. 35E uses thethree-ball-span configuration (3512) around the entirety of the cage.Such a bearing has the low friction advantages of a spherical ball butwould allow multiple concentric channels to be pumped at similarcompression levels.

The principle of operation and a diagram of one embodiment of an RPVmicrovalve are shown in FIGS. 36A-36C. FIG. 36A illustrates afour-channel valve in which the fluidic connections between inputs(3601) and outputs (3602) are interrupted by compression from the ballin the bearing at certain locations and contiguous at other locations(3603) such that only one channel of the valve's four channels is openat any given rolling element position. The principle of operation isillustrated in FIG. 36C with four rolling elements (3625) shown in fourdifferent positions (3621-3624) in which only one channel (3626-3629,respectively) is open to flow between the inputs and outputs. FIG. 36Bis a schematic drawing of a 16-port valve in which the outputs from 16switched inputs (3611) are combined at a single point in the center(3612). The meandering channels (3613) crisscross the radial position ofthe rolling element compression zone and are precisely positioned suchthat at each of sixteen angular positions of 8 rolling elements, onlyone input channel is open to the output and the remaining channels arecompressed by one or more rolling elements, forming a 16-port valve.

FIGS. 37A-37C show the concept, design, and functioning of oneembodiment of a pulse-width modulation RPV waveform generator. FIG. 37Aillustrates how the generator is composed of a continuous mixer thatuses alternating discrete pulses of two solutions as inputs. The bolusesmix together in a meander by diffusion and Taylor dispersion, forming anaxial output concentration waveform. By dynamically changing the lengthof the discrete pulses, multiple different concentration waveforms canbe produced at a wide range of temporal resolution. FIG. 37B is an imageof an axial gradient in a meander produced by manually alternatingbetween DI water and black dye. FIG. 37C is a schematic of theimplementation of discrete bolus mixing of two solutions using RPVs. Asthe compression zones of the rolling elements (3705) rotate, the twochannels (3706, 3707) are alternately closed. Positions 3701, 3702,3703, and 3704 show the four different states of the device formed by11.25 degree clockwise rotation of the rolling elements (3705). Inpositions 3701 and 3703, 3706 is closed, allowing fluid from 3707 toenter the meander (3708). In positions 3702 and 3704, 3707 is closed,allowing fluid to enter from 3706. The discrete boluses of the twosolutions mix in the meander (3708) and exit through the output port(3709). By dynamically varying the speed of the motor, arbitrary bolussizes can be created, allowing generation of different waveforms.

FIGS. 38A-38D illustrate the design and operation of a variable flowrate RPPM. FIG. 38A illustrates a device that pumps two fluids throughtwo separate channels (3807, 3808) from respective fluid inputs (3801,3803) to fluid outputs (3802, 3804), using two rolling elements (3805,3806) rotating at constant speed around a central axis and positionedopposite each other such that each fluid channel is always compressed byexactly one bearing. FIGS. 38B-38D illustrate device operation, as therolling element (3812) traverses the fluid channels (3811, 3821, 3831)and encounters an increasing number of channels as it progresses fromFIGS. 38B-38D. As the number of channels that rolling element (3812)compresses changes, pumping speed through the fluid channel changesproportionally, such that any flow waveform can be created with aspecific variation in channel multiplicity.

FIGS. 39A-39D illustrate a pulse regulating device with an input (3905)and an output (3906). As shown in FIG. 39A, when the standard device(3901) is operated, there is a period where the rolling element (3902)occludes the channels as they exit the device, which causes a stoppagein flow (3903). This in turn causes the flow from the device (3901) tobe pulsatile. However, the pulse regulator design shown in FIG. 39Bphases the channels out at different stages of rotation (3904),decreasing the pulsatility of flow from input (3905) to output (3906). Adetailed view of the phased exits is shown in FIGS. 39C-39D. As shown inFIG. 39C, the rolling element (3902) is early in the cycle, and isoccluding the exit of the third channel (3909) while the others remainopen and allow flow. FIG. 39D shows the rolling element (3902) late inthe cycle of rotation, labeled as 3910 occluding the exit of the lastchannel (3911).

FIG. 40A illustrates an RPPM configured as a two- or three-phase dropletgenerator. During operation, the actuator with six rolling elements(4001) (shown filled with hatch marks) rotates in a clockwise direction.The compression zones for each of the six rolling elements movecontinuously around the radius defined by the bearing geometry. Threecompression zones for each rolling element (eighteen total) are depictedas unfilled circles. Three microfluidic channels with inputs (4002-4004)follow precise pathways through the bearing compression zones andconverge at a single output (4005). Fluid can be pumped from the inputsof all three channels to the output in the pumping zone (4006) inreverse sequential order (4004, then 4003, then 4002).

During operation, each channel is occluded to prevent backflow withmeanders in the compression zones of non-pumping rolling elements(4007). The positioning of the compression zones ensures that thechannel being pumped in the pumping zone is not occluded, while theother two channels are occluded. This can ensure forward flow at thenexus and an interleaving of fluids from the three input channels. Ifimmiscible liquids are used on the inputs, droplets can be formed on theoutputs. Two-phase droplet mixtures can be obtained by eliminating oneof the three microfluidic channels, and if desired, enlarging theremaining two to maintain continuous, uninterrupted flow. If more thanthree fluidic phases or solutions are desired, additional channels maybe added in a similar configuration.

FIG. 40B illustrates an RPPM and RPV system that can act as both a fluidmultiplexer and a demultiplexer, depending upon the direction ofrotation. This extends the concept shown in FIG. 40A and demonstratesthe use of a single set of ball actuators to work as both a pump and avalve. With the balls rotating in a clockwise direction, the device actsas a multiplexer and draws fluid from three inputs and expels it througha single output. Fluid is first drawn from port 4011, with the pumpingsection 4014 providing the pressure to move the fluid, in contrast withthe device in FIG. 40A where an external pressure source is required.The return path 4016 allows the fluid to flow through to the output 4017by crossing the path of the balls at a location where the flow is notblocked by a ball when that section is pumping. After the ball movesfrom position A to position C, the pumping from 4011 stops because theball (shaded) encounters the blocking valve section 4015. Fluid ispumped from input 4012 when another ball reaches position B, andcontinues until that ball passes position A. Fluid is pumped from input4013 when another ball reaches position C, and continues until that ballpasses position B. The output 4017 contains the summed flow from 4011,4012, and 4013, as shown in FIG. 40C. The exact timing of the beginningand end of each pumping phase is determined by the exact angularposition of the pumping and blocking valve regions, and can be adjustedas desired in the design of the device. Hence, in this configuration,three different solutions can be multiplexed from the three inputs intoa common output. Similarly, rotation of the balls in a counterclockwisedirection causes the device to act as a demultiplexer that draws fluidfrom a single input 4017 and expels it through three separate outputs4011-4013. Other embodiments could produce multiplexers anddemultiplexers with different numbers of solutions and different timing.

FIG. 41A shows a profile view of one embodiment of a peristalsis systemin microfluidics. The microfluidic channel (4101) is compressed by arolling element (4102) (e.g., a ball bearing in certain embodiments)that is receiving downward force applied by a brass flange (4103) and aPDMS washer (4104). As rolling element (4102) rotates and moves alongthe microfluidic channel, the fluid or contents of the channel also movealong. FIG. 41B shows two schematics of embodiments of the RPPM. In theupper schematic, a single channel design depicts input and output punchpads (4111, 4112). Rolling elements (4113) show theoretical placement ofthe balls within a thrust bearing. The lower schematic of FIG. 39Breplaces a single channel configuration with five concentric channels(4114) that combine on ends. FIG. 41C is an exploded profile view of oneembodiment of an RPPM system. In this particular embodiment, a steppermotor (4121) is attached to a polycarbonate base piece (4122) by a setof four M3 screws (4123), and a brass flange (4124) is attached to themotor shaft by a 0-80 screw (4125). In the embodiment shown, the brassflange's shaft provides alignment and support for the PDMS washer (4126)and thrust bearing (4127). The microfluidic pump (4128) with tubing(4129) is placed between the thrust bearing and polycarbonate piece.FIG. 41D is a assembled version of FIG. 41C, while FIG. 41E shows aperspective view.

FIG. 42A shows a schematic for a compact embodiment of an RPPM. 4201 and4202 are the input/output ports for this design, which are connected to5 concentric channels (4203). Additional concentric circles (4204, 4205)are included for alignment. FIG. 42B shows the physical implementationof the compact embodiment illustrated in FIG. 42A. This implementationincludes a small stepper motor (4206), which is enclosed in a hollowthreaded rod (4207, secured to the motor housing with a set screw) andis screwed into the top half of a partially threaded hollow sleeve(4208). A brass flange (4209, secured to the motor shaft with a setscrew), allows a PDMS washer (4210) and ball thrust bearing (4211) to beplaced concentric to the motor's axis of rotation. The PDMS microfluidicdevice (4212) is placed on top of another hollow threaded rod (4213),which is then screwed into the bottom half of 4208. Tubing (4214) canthen be added to facilitate fluid flow. Threaded rod (4213) providesstructural support and height adjustment to microfluidic device (4212).Both threaded rods (4213) and (4207) can be used to control the amountof compression between the thrust bearing (4211) and PDMS microfluidicdevice (4212), which is a major factor in controlling flow.

FIG. 42C shows the unassembled parts used in another implementation ofthe embodiment shown in FIG. 42A. In this embodiment, a motor (4215) isdirectly attached to an acrylic housing (4216) with two hex socket headscrews (4217, 4218). A brass adapter (4221) is attached to the shaft ofthe motor with a set screw and supports the PDMS washer (4220) andthrust bearings (4219). In this embodiment, the microfluidic device andtubes (4222) are presented to the bearings and held in place by a hollowset screw (4223). FIG. 42D shows the assembled device, including4215-4223.

FIGS. 43A-43C show a design for a multi-pump array. This embodimentincludes three pairs of two pumps (4301 and 4302, 4303 and 4304, 4305and 4306), each of which is run through serpentine mixers (4307-4309).The middle pair is also run through a meander (4310) to allow forcontemporaneous flow. In this embodiment, the three channels are thencombined in a fourth serpentine mixer (4311). Parts of the largerstructure (FIG. 43C) are shown with dotted lines. These include screws(4312), motor heads (4313), and fastening plates (4314). FIG. 43B showsthe motor used in the array (4315). FIG. 43C shows a 3-D cutaway modelof the array, which shows the motor for the array (4315), the fasteningplates (4316), brass adapters (4317), PDMS washers (4318), thrustbearings (4319), PDMS device layer (4320), glass base (4321), and metalbase (4322). The fastening plates are supported by springs fromunderneath and held down by adjustable screws.

FIG. 44 shows the excellent linear relationship between flow rate(microliters/minute) and motor speed (revolutions/minute) exhibited byone embodiment of an RPPM. 4401 shows a schematic of the pump used togather this data. Each set of points (4402) (e.g., square, triangle,asterisk, open circle, and closed circle data points, as shown from topto bottom in the legend) has a linear trendline fitted to it. Theequations and R.sup.2 values for these trendlines (4403) are shown onthe left-hand side of the graph.

FIGS. 45A-45C show an embodiment exhibiting how two RPPMs may bearranged to provide two-dimensional control of particles in amicrofluidic device. FIG. 45A shows a schematic for the microfluidicdevice (known as a “crossflow” divide) used in 2-D control. One inputand one output of the first pump are connected via tubing to ports(4501) and (4502), respectively. The second pump's input and output areconnected to ports (4503) and (4504). The open chamber (4505) in themiddle of the device allows particles to move freely based on the flowstreams provided by the two RPPMs.

FIG. 45B shows the crossflow device and two RPPMs (4506 and 4507)configured to perform a 2-D control experiment. Tubing (4508) connectsthe two pumps to the crossflow device (4509). The microcontrollerplatform used to control this pump system (4510) is also shown. FIG. 45Cshows several kymographs created using this 2-D crossflow setup. Bysetting each RPPM to provide a sinusoidal input stimulus (with a 90degree phase shift between the two), particles can be moved in a circle,as shown in 4511. The 3-D graph (4512) shows the path of the particle inthe x- and y-axis and the progression of time in the z-axis. 4513 and4514 show 2-D side views taken from the 3-D kymograph.

FIGS. 46A-46C illustrate the design and operation of one embodiment ofan RPPM- and RPV-driven batch mode microformulator. In this embodiment,fluid inputs are selected from inputs (4601) of a rotary multiplexer(4602) and are drawn with an RPPM (4605) into a loading shuttle (4603)that holds inputs while RPPM (4605) flushes rotary multiplexer (4602)with solvent to the waste port (4606). Inputs in loading shuttle (4603)are then drawn into the mixing chamber (4604) and recirculated with RPPM(4605) until sufficiently mixed, at which point they are pumped out withRPPM (4605) through the output port (4607). In this exemplaryembodiment, mode switching of the device is achieved with an RPV (4608)that sequentially opens and closes channel paths with a thrust bearinglocated in the compression zone (4609). FIGS. 46B and 46C illustrate RPVoperation, as rolling elements (4611, 4612, 4621, 4622) sequentiallypass over compression zones (4613, 4623) of fluid channels (4614, 4615,4624, 4625) and successively open and close channel paths to switchbetween device operation modes.

FIG. 47 is a schematic representation of an alternative embodiment of ahigh-density array of microfluidic single-cell yeast traps. In thisschematic, 112 traps are shown in 7 rows of 16. In this exemplaryembodiment, each trap is 10 μm×10 μm, and the channel above each trap is10 μm wide. The ports are configured as pairs connected to a push-pullpump, using an on-chip peristaltic pump with either pneumatic or rotarymechanical actuation or a syringe pump pair, so that the flow from oneport is matched by the fluid removed from the other port of the pair. Inone exemplary method of use, a small number of yeast cells can be loadedby laminar flow along L1-L2 while all other ports are blocked. Once theyeast cells are loaded in a line along the left edge of the array, pumpsS1-S2 and S3-S4 are actuated transiently to move these cells from leftto right into the array.

In this embodiment, actuation of the transverse parallel flow from T1 toT2 will sweep the cells into the nearest trap. Adjustment of the T1-T2transverse flow can control the ability of the device to hold cells inthe traps, or modulate the trapping efficiency. S1-S2 and S3-S4 can pumpdifferent media formulations, e.g., different glucose concentrations. Agradient generator could be used to provide a different concentrationfor each row. In this schematic, there are four adult yeast cellstrapped, one of which is budding, and another whose bud has alreadymoved to the adjacent downstream trap.

In the embodiment shown, adjustment of the pumping rates of S1-S2 andS3-S4 relative to T1-T2 can lead to cells being trapped or swept all theway to the right, where a vertical fence of small posts detains thecells. Then optical sensing and computer-controlled valves V-A and V-Bcan direct flow from C1 cells to either outlet ports C2 or C3, dependingupon the cell type or genealogy. More outlet ports can be used to sortinto more categories. Adequate perfusion for low-density cultures can bereadily maintained with total flow through S1-S2 and S3-S4 of only 2mL/min. Activation of T1-T2 can provide perfusion without translation.Alternatively, flow from S1 to S2 and S3 to S4 will shift to the rightcells displaced from a trap by division. At 20× magnification, a typicalautomated fluorescence microscope can, in 40 ms, image a 430 μm×345 μmfield of view (FoV, each) in four colors with 0.3 μm×0.3 μm pixels. Bysequentially imaging 12 fields of view in 10 seconds, the high-speedtranslation of an automated microscope can allow a user to image 4000traps over a 1.3 mm×1.4 mm area in 10 seconds. The imaged area caneither be configured as one large trap array, or multiple, individuallycontrollable trap sub-arrays. One advantage of the latter is thatvertical perfusion can be continuous for all traps, but horizontal flowcould be limited to the interval where each sub-region is being viewedmultiple times by the microscope to track the cells as they move.

FIGS. 48A-48F illustrate steps towards implementation of the embodimentof FIG. 47. FIG. 48A illustrates an overall schematic of the device,while FIGS. 48B-48F provide more detailed views of different sections.While the figures in the present disclosure are generally not to scale,FIGS. 48A-48E are shown to scale for one exemplary embodiment. In FIG.48A, the scale bar represents 1 cm. In FIG. 48B, fluid flow is driven byan on-chip RPPM, and the scale bar is equal to 500 μm. In FIG. 48C, aMoire interference pattern for accurate low-cost mask alignment isillustrated, with a scale bar equal to 400 μm. In FIG. 48D, a valvesystem that allows integrated cell sorting is shown. In this figure, thescale bar equals 800 μm. In FIG. 48E, an array of cell trap devices isillustrated with a scale bar equal to 60 μm. FIG. 48F illustrates aComsol hydrodynamic model of cell retention force under perfusion in aselection of trap designs. Surface shading represents fluid velocitymagnitude, and vector arrows represent normalized average total shearstress on primary trapped cells (top row) and secondary trapped cells(bottom row).

FIG. 49A shows an embodiment utilizing rotary thrust ball bearings asplanar valves to drive serial switching between three different flowconfigurations. In this embodiment, rolling element spacing within thecage (4901) allows for three unique positions. Rolling element spacingcan be modified to allow for more configurations. Additionally, thisconfiguration of nanobioreactor and channel positioning can be arrayedaround the cage to control multiple switching events in a singlerotation. A compression between the rolling element-PDMS interfaceforces any underlying microfluidic flow channels shut. Rotation of thebearing cage allows for only one open flow path at branch sites (4902,4903) so that nanobioreactor A and B (4904, 4905) can operateseparately, as shown in FIG. 49B, or in series, as shown in FIGS.49C-49D.

FIG. 49B shows a rolling element (e.g., ball bearing) configuration thatallows for independent perfusion of nanobioreactor A and B (4904, 4905).These unique rolling element positions close off channels that connectflow between the nanobioreactors (4911, 4912) and the outlet port usedwhile operating in series from nanobioreactor A to B (4913). Thus, thisrotation state leaves only two open outlets (4914, 4915) for independentperfusion of nanobioreactor A and nanobioreactor B.

Subsequent clockwise rotation of the rolling element cage to the nextunique state is shown in FIG. 49C. Rolling element positions (4921,4922) close output flow channels for nanobioreactor B and re-routeoutput flow of B to nanobioreactor A (4923). Flow from nanobioreactor Ato B is occluded as well (4924), forcing flow to a single output channel(4914).

Further clockwise rotation of the rolling element cage to the lastunique state is shown in FIG. 49D. Rolling element position (4931)blocks the outlet port downstream of nanobioreactor A, forcing flowthrough a connecting channel (4932) from A to nanobioreactor B. Seriesflow from nanobioreactor B to A is prevented as this channel (4932) isforced shut due to ball bearing compression (4933). Additionally, asingle outlet port (4934) remains open as ball bearing (4932) shuts flowto the second outlet port of nanobioreactor B (4915).

FIG. 50 illustrates the design of an RPPM-driven and Quake-stylevalve-controlled batch mode microformulator. Fluid inputs are selectedfrom inputs (5001) of a multiplexer (5004) controlled with Quake valvechannels (5002) and are drawn with an RPPM (5007) into a loading shuttle(5009) that holds inputs while 5001 is flushed with solvent to the wasteport (5005). Inputs in 5004 are then drawn with 5007 into the mixingchamber (5008) and recirculated with 5007 until sufficiently mixed, atwhich point they are pumped out with 5007 through the output port(5006). Mode switching is achieved with Quake valve channels (5003) thatsequentially open and close channel paths.

FIG. 51 shows the concept, design, and operation of a Quantum DotHybridizer. FIG. 51A is a schematic showing the agglomeration of quantumdots (QDs) and antigens in a closed recirculating microfluidic channel.With each hybridization cycle, the agglomerates grow larger until theycan be easily detected. FIG. 51B is a schematic showing how an RPPM andpneumatic valves are combined to implement re-circulatory flow. Thedevice consists of connected flow channels (5104) and three controlchannels that act as valves (5101, 5102, 5108). When 5101 and 5108 arepressurized, the fluidic inputs (5103) are closed, allowing forcirculation of fluid by rotation of the RPPM's bearings (5105). Whenonly 5102 is pressurized, fluid can enter and exit the system throughthe fluid ports (5103). The branched mixer (5107), which is composed ofmultiple meanders of varied lengths (5106), allows for rapid mixing.

FIG. 51C shows the device (5109) with the motor and rolling elements setup to re-circulate and mix lighter and darker dyes (with the darker dyesbeing at the upper portions of the meanders). 5110, 5111, and 5112 aretime series images of the mixer at the start, middle, and end of mixingby counter-clockwise rotation of the bearings. FIG. 51D is an image ofthe device after mixing lighter and darker dyes.

Rotary planar peristaltic micropump (RPPM) and rotary planar valve (RPV)technologies can also be combined into a well-plate assay controller.Since the same DC gear-head or stepping motor configuration can be usedto drive both the RPPMs and the RPVs, the development on an integratedmicrofluidic control unit is attainable. The RPPMs and RPVs can be usedin tandem to create general purpose instrumentation that can deliver,for example, within one minute a microliter of solution that is meteredand mixed from multiple reservoirs whose relative contributions can becontrolled on demand. The RPPMs can be used to drive the fluid throughthe systems and the RPVs will regulate flow to the desiredinlet/outlets. Various reagent reservoirs for priming buffer, coatingchannels with desired matrix, cells, cell media, test sample and washbuffer will be considered to facilitate the implementation of assayprotocols.

A typical well-plate assay with live cells can involve two modes. Thefirst mode is a “preparation mode,” which consists of priming thedevice, cell matrix injection, and cell injection followed by mediainjection until cells are confluent. A wash and suction step isintegrated for waste removal. The second mode is an “assay mode,” whichrefers to the test conditions where different samples (nutrients,xenobiotic compounds, drugs, and pathogens) are evaluated for theireffects on the cells being cultured.

In this embodiment, each of these modes is supported by a separateRPPM-RPV device. FIG. 52A shows the device that supports the PreparationMode. RPV 1 (5201) selects one of six inputs (5211-5216), RPPM 1 (5202)with rotating elements (5203) provides the pumping through the device,and a Y-channel or connector header (5204) provides the connection ofthe Preparation inputs to the input ports (5205) of the well plate,shown in FIG. 53. While 12 chambers are shown for convenience, theactual number could be different, either larger or smaller.

The Assay Mode shown in FIG. 52B has RPV 2 (5206) that selects from sixinputs (5217-5222), and the output of this valve goes to RPPM 2 (5207).The output of this pump then goes into a selector valve RPV 3 (5208),which determines which input fluid is injected through the connector5209 and hence well-plate assay ports 5210 and then to the selected,individual chamber in the well plate.

FIG. 52C shows an alternative embodiment for the Assay Mode, in whichthe output from RPPM 2 (5207) connects to RPV 3′ that is similar to 5208but with an additional valve position (5230) that is connected to acommon set of ports (5234) in RPV 4 (5232). This 12-position RPV (5232)switches from random access to parallel flow for media flow, in a mannerdesigned to eliminate crosstalk between the bioreactors until they arefed by the common line from the 13^(th) position in RPV 3′ (5231). Forthe serial loading of individual chambers in the well plate, asdescribed in FIG. 52B, the selection of connections (5235) in RPV 4(5232) connects each of the first 12 outputs of RPV 3′ (5231) valveinputs (5233) to the corresponding well-plate connector and port in 5209and 5210. In this embodiment, when RPV 4 is switched to the otherposition, the connections 5235 are made to the common ports (5234), andthe output of RPPM 2 (5207) is directed in parallel to all twelve of thechambers through each line in 5209 and 5210. A particular advantage ofthis particular arrangement is that the 12 chambers in the well platecan be either addressed individually for loading, drug dosing, oranalysis without cross contamination, or perfused in parallel to allowlong-term culture without the need to use the RPVs actively to multiplexperfusion through all wells individually.

The well-plate controllers in FIGS. 52A-52C could be connected to thewell plate in FIG. 53. The connector from the Preparation Modecontroller (FIG. 52A) connects to the ports 5205, while those from theAssay Mode Controller (FIGS. 52B-52C) connect to ports 5210. Each ofthese ports is connected to a perfusion line, for example, 5201 and5202, respectively. The use of two separate lines reduces thepossibility that cell debris or other materials from the loading processwill interfere with the assay process and could be eliminated ifdesired. Each of the preparation and loading lines converges on anindividual microfluidic chamber, device, or fluidic network, as shownfor example by 5303. Each chamber, device, or network is connected to anindividual drain line, e.g., 5304, and these lines are gathered togetherto form drain connections 5305 from the device. Other embodiments wouldbe possible based upon this example.

The discussion below summarizes an automated well-plate loading andassay process, using the controller in FIG. 52 and the 12-well plate inFIG. 53 as an example. The process comprises the following sequences:

Preparation Mode

1. Stainless steel Y connectors into the inlet of each device withsealable plug to choose the port for injection in the 12 wells.

2. Four reservoirs for priming media, cell growth matrix, cells and cellculture media/harvesting media connected to a 6-position RPV for: Off,wash, matrix, cells, media, harvest.

3. An RPPM draws fluid from the valve and pressurizes the well plate forinitiating the valve-based sequential operation.

4. A single tube goes to a disposable output connector with a built-insplitter for 12 Y-As. A blank termination tube goes to the 12 Y-Bs foruse in the assay mode.

Assay Mode

In this embodiment, we illustrate how to investigate the effects of fourdifferent drugs on a total of twelve separate cell populations.

1. Five reservoirs for media+four drug solution reservoirs.

2. Six-way RPV for Off, media, four drug solutions.

3. An RPPM interconnected to a 13-position RPV for individual welladdressing or parallel addressing of all wells.

4. An RPV that can switch from serial individual loading to parallel,simultaneous perfusion.

Using the layout in FIG. 43, a set of six of motors that could bemounted in a manner to implement FIGS. 52A-52C, with differentmicrofluidic channels, to create a compact RPPM-RPV microfluidic controlunit, which would thereby replace with a single unit all the hardwareand tubing required by macroscopic laboratory implementations ofmicrofluidic well-plate loading. Such a system would result in anintegrated fluidic controller for a high-throughput assay. This systemcould then be utilized in standard microscopes, automated microscopes,high-throughput plate readers, and high-content screening automatedmicroscopes, as well as being integrated into stand-alone instrumentsthat contain the requisite optical and mechanical components.

One notable feature of this pump and valve system over other approachesis that a common motor and controller design can be used to controleither a pump or a valve; the components are of sufficiently low costthat they can be implemented as individual support units for each wellplate being assayed, and the devices are sufficiently compact that theycould be placed inside a sterile, cell-culture incubator.

FIGS. 54A-54D illustrate an embodiment of an RPPM device that maintainsa constant flow rate without pulsatility. FIG. 54A depicts an RPPM witha U-shaped channel (5401) compressed by rotating bearings (5402) thatpumps fluid from an inlet (5403) to an outlet (5404). FIG. 54Billustrates the mechanism by which pulsatility forms in such a device.As the bearing (5412) rotates and travels away from the fluid channel(5411), the area of the channel once compressed by 5412 is no longercompressed and expands to its normal height, thereby drawing in fluid tofill the expanding channel and temporarily reducing output flow. Onemethod to eliminate this output pulse is to temporarily increase rollingelement rotation speed as the event in FIG. 54B occurs, thus increasingoutput flow by an amount equal to the pulsed reduction in flow. FIG. 54Cillustrates a second device, identical to FIG. 54A except for a channelmodification (5431), designed to eliminate pulsatility while maintainingconstant bearing rotation. FIG. 54D illustrates the function of thedevice, as rotating rolling elements (5441, 5444) compress a channel(5442) and pump fluid through 5442. As the last rolling element (5444)leaves the channel area, the previous rolling element (5441) compressesan expanded area of the channel (5443) and pumps an additional volume offluid equal to the fluid lost through pulsatility.

While exemplary embodiments of the present invention have been shown anddescribed in detail above, it will be clear to the person skilled in theart that changes and modifications may be made without departing fromthe scope of the invention. As such, that which is set forth in thepreceding description and accompanying drawings is offered by way ofillustration only and not as a limitation.

In addition, one of ordinary skill in the art will appreciate uponreading and understanding this disclosure that other variations for theinvention described herein can be included within the scope of thepresent invention.

In the preceding Detailed Description of Disclosed Embodiments, variousfeatures are grouped together in several embodiments for the purpose ofstreamlining the disclosure. This method of disclosure is not to beinterpreted as reflecting an intention that exemplary embodiments of theinvention require more features than are expressly recited in eachclaim. Rather, as the following claims reflect, inventive subject matterlies in less than all features of a single disclosed embodiment. Thus,the following claims are hereby incorporated into the DetailedDescription of Exemplary Embodiments, with each claim standing on itsown as a separate embodiment.

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What is claimed is:
 1. A peristaltic micropump, comprising: multipleflexible channels configured to transfer one or more pumped fluids; anactuator configured to engage the multiple flexible channels, and rotateabout a central axis, wherein the actuator comprises two or more rollingelements, each rolling element having a geometric center, and a drivingelement configured such that the driving element operably rotates aboutthe central axis and each rolling element operably rolls about arespective axis that is not parallel to the central axis, wherein thetwo or more rolling elements are disposed between the multiple flexiblechannels and the driving element; wherein the driving element comprisesa cage configured to capture the two or more rolling elements such thatthe geometric centers of at least two of the two or more rollingelements are located at different radii having different distances froma center of the cage; wherein the multiple flexible channels comprisemultiple concentric channels located at different radii having differentdistances from the center of the cage; and wherein the driving elementand a surface of a bulk material that contains the multiple flexiblechannels have a coefficient of friction that is substantially matched toeach other, and the driving element and the bulk material that containsthe multiple flexible channels have a coefficient of elasticity that issubstantially matched to each other.
 2. The peristaltic micropump ofclaim 1, wherein the driving element and the bulk material that containsthe multiple flexible channels are comprised of a flexible polymericcompound.
 3. The peristaltic micropump of claim 1, wherein the drivingelement and the bulk material that contains the multiple flexiblechannels are comprised of polydimethylsiloxane (PDMS).
 4. Theperistaltic micropump of claim 1, wherein each rolling element isconfigured to rotate about an axle.
 5. The peristaltic micropump ofclaim 1, wherein the two or more rolling elements comprise a pluralityof ball bearings.
 6. The peristaltic micropump of claim 1, wherein thetwo or more rolling elements comprise a plurality of cylindricalrollers.
 7. The peristaltic micropump of claim 1, wherein the two ormore rolling elements comprise a plurality of conical rollers.
 8. Theperistaltic micropump of claim 1, wherein the driving element comprisesa rotating drive mechanism and a centering component configured tocenter the cage with respect to the rotating drive mechanism.
 9. Theperistaltic micropump of claim 1, wherein the multiple concentricchannels are arranged in a single channel section.
 10. The peristalticmicropump of claim 9, wherein the multiple concentric channels arefluidically connected to an input node and an output node.
 11. Theperistaltic micropump of claim 10, wherein each of the multipleconcentric channels is fluidically connected to the input node and theoutput node.
 12. The peristaltic micropump of claim 9, wherein each ofthe multiple concentric channels is fluidically and directly connectedto a respective input node and a respective output node.
 13. Theperistaltic micropump of claim 2, wherein the multiple concentricchannels are arranged in multiple channel sections.
 14. The peristalticmicropump of claim 13, wherein the multiple channel sections arespatially and fluidically separated from one another, and whereinchannels of each channel section of the multiple concentric channels arefluidically connected to a respective input node and a respective outputnode.
 15. The peristaltic micropump of claim 13, wherein the multiplechannel sections have a first multiple channel section and a lastmultiple channel section, and are spatially and fluidically connected toone another except that the first multiple channel section and the lastmultiple channel section are spatially and fluidically separated fromone another, and wherein the first multiple channel section and the lastmultiple channel section are fluidically connected to an input node andan output node, respectively.